Ultrathin Uniform Platinum Nanowires via a Facile Route Using an

May 21, 2018 - The fabrication is simply achieved using an inverse hexagonal (HII) ... by the need to meet the increasing demand for renewable energy,...
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Ultrathin uniform platinum nanowires via a facile route using an inverse hexagonal surfactant phase template Samina Akbar, Jacob Boswell, Carys Worsley, Joanne M Elliott, and Adam M. Squires Langmuir, Just Accepted Manuscript • DOI: 10.1021/acs.langmuir.7b03970 • Publication Date (Web): 21 May 2018 Downloaded from http://pubs.acs.org on May 21, 2018

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Figure 3. TEM micrographs of Pt-nanowires fabricated from the HII phase of phytantriol in the presence of 0 % (left) and 4.1 % (right) (w/w) tricosene at 55 and 25 °C respectively. The fabrication time was 6 hours. 683x1113mm (72 x 72 DPI)

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Ultrathin uniform platinum nanowires via a facile route using an inverse hexagonal surfactant phase template Samina Akbar,a,b Jacob Boswell,c Carys Worsley,c Joanne M. Elliott,*a and Adam M. Squires*ac a

Department of Chemistry, University of Reading, Whiteknights, Reading, RG6 6AD. Fax:

(+)44 (0)118 378 6331, E-mail: [email protected], [email protected], Homepage: http://www.reading.ac.uk/chemistry/chem-home.aspx b

Department of Basic Sciences and Humanities, University of Engineering and Technology,

KSK Campus, GT Road Lahore, Pakistan. c

Department of Chemistry, University of Bath, Bath BA2 7AY, UK

KEYWORDS. Self assembly, Inverse Hexagonal, Templating, Platinum, Nanowires

ABSTRACT. In this paper, we present an attractive method for the fabrication of long, straight, highly crystalline ultra-thin platinum nanowires. The fabrication is simply achieved using an inverse hexagonal (HII) lyotropic liquid crystal phase of the commercial surfactant phytantriol as a template. A platinum precursor dissolved within the cylindrical aqueous channels of the liquid crystal phase is chemically reduced by galvanic displacement using stainless steel. We demonstrate the production of nanowires using the HII phase in the phytantriol/water system

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which we obtain either by heating to 55 °C, or at room temperature by the addition of a hydrophobic liquid, 9-cis-tricosene, to relieve packing frustration. The two sets of conditions produced high aspect nanowires with diameters of 2.5 nm and 1.7 nm respectively, at least hundreds of nanometers in length, matching the size of the aqueous channels in which they grow. This versatile approach can be extended to produce highly uniform nanowires from a range of metals.

INTRODUCTION. Nanostructured platinum materials have been investigated for a wide range of high-surface-area applications. Some of these technologies are driven by the need to meet the increasing demand for renewable energy, for example, in fuel cells1 and solar cells2. Other applications include sensors3 and chemical catalysts4-5. The use of nanowires rather than the commonly used supported nanoparticles brings a number of advantages, overcoming several problems associated with the latter especially in fuel cells, such as support degradation, particle sintering, and limitations on catalyst loading1. Ultrathin platinum nanowires have been shown to exhibit higher electrochemical surface area activity than supported nanoparticles6, and greater electrochemical durability under voltage cycling5. In other applications, platinum nanowires bring new optical7, magnetic8 and catalytic properties9-10. More generally, ultrathin nanowires from other metals have applications in transparent conducting electrodes11. A number of approaches have been used to produce ultrathin (